Automatic parachute-opening device



Nov. 26, 1963 s. L. SNYDER 3,112,091

AUTOMATIC PARACHUTE-OPENING DEVICE Filed May 4, 1960 I5 Sheets-Sheet 1 I5 3g 33 4O INVENTOR 'tepliemLs z lder Nov. 26, 1963 s. SNYDER 3,112,091

AUTOMATIC PARACHUTE-OPENING msvxcs Filed May 4, 1960 3 Sheets-Sheet 2INVENTOR Nov. 26, 1963 s. 1.. SNYDER AUTOMATIC PARACHUTE-OPENING DEVICE3 Sheets-Sheet 3 Filed May 4. 1960 um llil llllll United States Patent3,112,091 AUTOMATIC PARACHUTE-OPENING DEVICE Stephen L. Snyder,Swarthmore, Pa. (3939 Lankenau Road, Philadelphia 31, Pa.) Filed May 4,1960, Ser. No. 26,864 20 Claims. (Cl. 244-150) This invention relates toa device for manually or automatically opening a parachute at apredetermined altitude, and it more particularly relates to a simple andcompact form of such a device which is conveniently adjustable tocompensate for variations in atmospheric pressure and ground level.

The sport of sky diving has recently become quite popular and emphasizedthe need for a dependable and economical automatic parachute-openingdevice because inexperienced jumpers are prone to freeze and fail topull the ripcord in the excitement of a drop, and even experienced skydivers have for unexplained reasons failed to release their chutes withdisastrous results. One explanation I for the failure of experienced skydivers to pull the rip cord is hypnotism caused by the whirling motionduring a fall, but for whatever reason they have not pulled the cord atthe prescribed 2,000 foot minimum altitude, an accurate, economical anddependable automatic parachute-opening device would be a boon to them aswell as to novices. Various automatic devices which are actuated bybarometric pressure-sensing means have been proposed for automaticallyopening parachutes at predetermined altitudes. However, they are notadapted for convenient adjustment by the jumper himself to compensatefor variations in ground level and atmospheric pressure, and they havebeen fairly bulky and complicated.

It is, therefore, an object of this invention to provide a compact,simple and economical device for automatically opening parachutes atpredetermined altitudes.

Another object of this invention is to provide such a device which isreadily adjustable by the jumper himself to compensate for variations inground level and atmospheric pressure.

In accordance with this invention an extremely simple and dependabledevice for manually or automatically opening a parachute includes anautomatically-actuable drive means mounted upon the parachute pack withits line of action disposed substantially parallel to the line of actionof the ripcord pins and attached to the ripcord be tween the ripcordhandle and the pins before it substantially deviates from the line ofaction of the pins. An altitude-sensing and signalling means isconnected through an actuating circuit to the automatically-actuabledrive means for causing it to open the parachute at a predeterminedminimum altitude. The ripcord can also be manually pulled by the handle,and the aforementioned disposition of the drive means allows it to actdirectly upon the pins which minimizes the force required for absolutelydependable operation and the size and complexity of the drive means. Themanually-pulled handle may, for example, be directly mounted upon theautomatic drive for a front-mounted pack or connected to it for lessaccessible packs such as back-mounted packs.

A simple and economical altitude-sensing and signalling means foractuating the automatic drive means includes an altimeter having avisible movable altitude-indicating element and an associated visiblereference element which is manually-adjustable to permit adjustment ofthe reference element to the ground level position of the movableelement thereby compensating for atmospheric pressure variations. Thisdevice conveniently utilizes the structure of a standard barometricaltimeter having a movable needle and an adjustable face with itssignalling means including a switch having one of its contacts mountedin a predeice termined position relative to the face and the other ofits contacts incorporated upon the needle.

Novel features and advantages of the present invention will becomeapparent to one skilled in the art from a reading of the followingdescription in conjunction with the accompanying drawing wherein similarreference characters refer to similar parts and in which:

FIG. 1 is a top plan view of a parachute pack upon which one embodimentof this invention is mounted;

FIG. 2 is a rear view in elevation of the parachute pack and embodimentshown in FIG. 1;

FIG. 3 is a front view in elevation of the ripcordpulling portion of theembodiment shown in FIGS. 1 and 2;

FIG. 4 is a front view in elevation partially broken away in crosssection of the portion shown in FIG. 1 in readiness for actuation;

FIG. 5 is a front view in elevation of the portion shown in FIG. 4 afterit has been automatically actuated;

FIG. 6 is an enlarged cross-sectional view of the detonating portion ofthe embodiments shown in FIGS. 4 and 5;

FIG. 7 is a schematic diagram of electrical and mechanical elements ofthe altitude-sensing and signalling portion of the embodiment shown inFIG. 1 in the unarmed condition in its association with ripcord-pullingunit;

FIG. 8 is a plan view of the altitude-sensing and signalling portionsshown in FIG. 7 in the armed condition;

FIG. 9 is a cross-sectional view taken through FIG. 8 along the line9-9;

FIG. 10 is a side view in elevation of the embodiment shown in FIGS.3-5;

FIG. 11 is a perspective view of a portion of the embodiment shown inFIG. 7; and

FIG. 12 is a schematic view of another embodiment of this invention.

In FIGS. 1 and 2 is shown an automatic parachuteopening device 10mounted upon a parachute pack 12 which is, for example, of the emergencytype used by a sky diver. An instrument panel 14 is mounted upon theportion of the pack facing the jumper, and an altimeter 16 and stopwatch 18 are customarily mounted upon this panel to inform the jumper ofhis altitude and duration of fall. Altimeter 16 has a movablealtitude-indicating element, such as a needle, and a reference element,such as a face, which is adjustable to zero it at ground level beforeascent. This type of adjustability is provided in conventionalaltimetcrs, and an example of it is shown in US. Letters Patent2,465,775. An aneroid barometer type of altimeter is described in FIG. 4of US. Letters Patent No. 2,367,034. Hooks 19 extend from pack 12 tofasten it to the body of the jumper and straps 21 facilitate itstransportation.

Parachute-opening device 10 includes an automaticallyactuated drivemeans 11 incorporating a hollow cylinder secured to ripcord handle 22.Special switching elements are generally designated in FIG. 1 byreference numeral 24, and they are associated with altimeter 16 andelectric triggering circuit wires 26 which are connected by a readilydetachable coupling plug and socket 28. Cylinder 20 is mounted within astandard unmodified pocket 30 attached to the cover of pack 12, and itis connected to ripcord 32 in a manner later described in detail forautomatically pulling it and its parachute-securing pins 34 out of cones36 to release securing buckles 38 and allow the parachute to be openedby elastic bands 40. An electric battery 42, later described in detail,is connected to triggering circuit wires 26, and it is convenientlysecured by clamp 44 to the rear of altimeter 16.

FIGS. 35 show the details of cylinder 20 and its manner of associationwith ripcord handle 22 in various phases of operation together with themode of connection a of ripcord handle 22 and actuating cylinder 20 withripcord 32. FIG. 3 shows the overall association of these elements inthe condition where they are ready for actuation either by manual orautomatic means.

Ripcord handle 22 is secured to ripcord 32 by mounting it uponautomatically-actuated drive means 11 as shown in FIGS. l5 or, as shownin FIG. 12 by connecting it to drive means 11a. The disposition of thedrive means between the ripcord and handle at a location before itsubstantially deviates from the line of action of the pins causes it toact directly upon the pins and unexpcctedly simplifies its structure.Furthermore, this permits the remarkably convenient attachment of thehandle to the drive means to provide a device which is alternativelymanually or automatically actuated. In FIG. 12 handle 22a is connectedto drive means 11a by a cable 23a which transmits a manual pull to pins34a and disconnects electrical coupling 280.

Details of cylinder and its associated elements are shown in FIGS. 4 and5 respectively in the ready and actuated conditions. In FIG. 4 piston isshown in its ready condition disposed adjacent explosive unit 52. It is.for example, inherently maintained in the ready position adjacentexplosive unit 52 which is, for example, a commercially availableigniting and detonating unit of the type shown in FIG. 6 which includesinsulated igniting wires 56 extending through screw plug 58 into itshollow chamber 60. An explosive charge 62, for example, incorporatingfast-burning powder is enclosed within chamber 60 by a sea] 64, forexample, made of aluminum or a suitable plastic. A thin bridge wire 66connects igniting wires 56 within chamber 60, and a bead primer 68 isattached to bridge wire 66 for helping initiate the detonation of powdercharge 62. Various other forms of detonators and powder charges may beutilized for the illustrated purpose as well as spring-powered devices.However, illustrated unit 52 is highly convenient because of itscompactness and ease of reloading.

In FIG. 5, piston 50 is shown in its extremity of ripcord-pulling travelafter explosive unit 52 has released its gas charge. Piston 59 has,through ripcord cable 48 connected to it, withdrawn pins 34 from cones36 thereby permitting buckles 38 to be released and permit the parachuteto open. At its terminal extremity of travel one end of piston 50' hascontacted elastic buffer 70 made of hard fibre which absorbs itsremaining energy whose dissipation is facilitated by the connection ofchamber 72 within cylinder 20 to atmospheric pressure through slot 74which allows the expanding gases to dissipate into the air when the end76 of piston 50 exposed to the gases uncovers slot 74. The end ofripcord cable 48 is conveniently connected in operative position topiston 50 by inserting it through a slanted aperture 77 in the side ofpiston 59 and securing its end 75 which is enlarged by attached ring 79within a cavity 81 in the end of piston 50. This substantially straightmode of connection keeps piston 50 adjacent explosive unit 52 as long aspins 34 are inserted within cones 36. In FIG. 10 cable 48 is showninclined at an angle to the vertical along the slot 74 which is turnedtoward the path of action of ripcord pins 34 to minimize frictionalresistance. The base 49 of handle 22 is bent away from pack 12 to makeit more accessible.

FIGS. 7-9 show details of actuating circuit 78 and interconnectedportions of cylinder 20, altimeter 16 and various electrical switchingelements which are now described in detail. Electrical circuit 78includes wires 26 connecting battery 42, represented schematically inFIG. 7, with arming and switching element movably mounted adjacentaltimeter face 82 and altimeter needle 84. \Vires 26 are connectedthrough detachable coupling 28 in the previously described manner withexplosive unit 52 fastened in the end of cylinder 20. These wires alsoconnect battery 42 with a stationary contact 86 secured to altimeterface 82 through a wire 88 passing under face 82, and the other side ofthe circuit is connected through a grounding wire 9i) to the metalmechanism of altimeter 16- and through it to altimeter needle 84.Battery 42 is, for example, a mercury cell of the type providing 1.3volts and 0.2 ampere. This type of cell is light and compact as well ashaving a long shelf life, and its aforementioned voltage and amperageare quite sutficient for igniting an explosive unit 52 incorporating anigniter and detonator of the type described which consistently detonateswhen actuated by the aforementioned voltage and current.

Switching and signalling element 80 is, for example, sector shaped andpivoted concentrically with needle 84 and attached to amanually-operable knob 92. It includes a foot 94 which is engagcable asshown in FIG. 9 under stationary spring contact 86 to arm the triggeringcircuit. The armed" condition is indicated as shown in FIG. 8 to theparachute jumper by display of the Word armed" through elongated slot 98in switching element 80 when foot 9 4 is engaged under spring contact86. The off" position is shown in FIG. 7 Where foot 94 is engaged underspring clip 87 which is for convenience made similar in structure tocontact 86 although it has no electrical function. These structures areshown in detail in FIG. 11 which shows dual spring fingers 89 and 91which respectively engage the fiat of foot 94 and the space 93 betweensplit toes 95 and 97. This structure insures firm engagement andelectrical contact. A contact is mounted in the form of a pin extendingfrom the surface of switching element 80 adjacent altimeter face 82 inthe path of movement of altimeter needle 84. Contact I09 is arranged tobe engaged by needle 84 at the onethousand foot altitude when foot 94 isengaged with fixed Contact 86-. This detonates explosive unit 52 toautomatically open the parachute at the one-thousand foot altitude if ithas not been opened sooner by a manual pull of the ripcord. A manualpull of the ripcord disarms the triggering circuit 78 by the opening ofwire coupling 28 to prevent explosion of the charge after the ripcordhas been manually pulled.

Operation At the ground level switching element 80 is maintained in theunarmed position shown in FIG. 7 providing an open triggering circuit78, and the altimeter face is zeroed through knob 102 shown in FIG. 1and actuating gears 104 and 106 shown in FIG. 7 to cause needle 84 toindicate a zero altitude at ground level regardless of the atmosphericpressure on a given day. This sets the contact on the sector when movedto the armed position at a point which will be contacted by the needleat the exact altitude to which it is set, and it insures that theparachute will open consistently at the one-thousand foot altitude abovestarting ground level regardless of the existing atmospheric pressure onthe day of the jump.

After the jumper has reached an altitude above the one-thousand footlevel and there is no danger of premature detonation, switching element80 is moved from the Off" position shown in FIG. 7 to the Armed positionshown in FIG. 8 to complete the triggering circuit. This condition ofreadiness is indicated to the jumper by display of the word Armedthrough slot 98 as shown in FIG. 8, and security in the Otf" position isdemonstrated when the word Off is visible along the side of the sectoras shown in FIG. 7.

On the way down the jumper should pull the ripcord at two thousand feet;however, if for some reason he fails to do so, the chute will beautomatically opened at one thousand feet in the manner previouslydescribed when needle 34 engages contact 100 on the underside of switch80 as shown in FIG. 8 to complete the triggering circuit and detonatethe charge.

What is claimed is:

l. A device for opening a parachute pack secured by pins attached to aripcord and inserted into cones comprising an electrically-actuateddrive means including a movable clement mounted within a stationaryportion, an altitudesensing means for providing a signal at apredetermined altitude, an actuating circuit connecting said sensingmeans to said drive means for causing it to propel said movable elementin response to said signal, coupling means connecting said movableelement with said ripcord to permit said ripcord to be pulled, pocketmeans upon said pack having an opening disposed in a position remotefrom said cones, said pocket means being substantially closed in aposition adjacent said cones for securing said drive means againstmovement towards said cones, said pocket means being mounted upon aportion of said pack closely adjacent to said pins with a line of actionextending through said opening aligned with the line of action of saidpins, said drive means being inserted within said pocket which disposesits line of action in line with that of said pins with said opening insaid pocket, and a handle being directly connected to said stationaryportion of said drive means to permit said ripcord to be manually pulledthrough said coupling which connects said movable element of said drivemeans to said ripcord.

2. A device as set forth in claim 1 wherein said drive means is disposedimmediately adjacent said pin means, and said handle is connected tosaid stationary portion of said drive means by a cable.

3. A device as set forth in claim 1 wherein said handle is rigidlymounted upon said stationary portion of said drive means.

4. A device as set forth in claim 1 wherein said drive means includes apiston disposed within a cylinder, and coupling means connects saidpiston to said ripcord.

5. A device as set forth in claim 4 wherein said coupling means is aportion of said ripcord which connects said piston to said pin means.

6. A device as set forth in claim 4 wherein an explosive means isattached to the end of said cylinder remote from said handle.

7. A device as set forth in claim 6 wherein a longitudinal slot extendsthrough the side of said cylinder along the path of travel of saidpiston, and said coupling means extends through said slot from saidpiston to said ripcord.

8. A device as set forth in claim 6 wherein a longitudinal slot extendsthrough the side of said cylinder along the terminal portion of travelof said piston, and said slot being slightly longer than said piston toexhaust said cylinder to the atmosphere at the terminal portion oftravel of said piston for minimizing the shock of said piston when itimpinges upon the terminal end of said cylinder.

9. A device as set forth in claim 3 wherein said drive means includes apiston disposed within a cylinder, an explosive means is attached to theend of said cylinder, igniting wires are connected to said explosivemeans, and a detachable coupling is inserted within said igniting wiresfor disconnecting said igniting wires from said explosive means todisarm said drive means when said handle is manually pulled.

it). A device as set forth in claim 3 wherein said connected handle anddrive means are both installed within said pocket.

11. A device as set forth in claim 7 wherein said handle is mounted uponsaid cylinder, and said longitudinal slot is substantially aligned witha plane including said ripcord and the longitudinal centerline of saidcylinder to minimize the frictional resistance imposed upon saidcoupling means.

12. A device for opening a parachute pack secured by pins attached to aripcord comprising an automaticallyactuable drive means having movableand stationary portions, an altitude-sensing means for providing asignal at a predetermined altitude, an actuating circuit connecting saidsensing means to said drive means for causing it to operate at apredetermined altitude, coupling means connecting a movable portion ofsaid drive means with said ripcord for pulling said cord, a handle beingconnected to said automatically-actuable drive means to permit saidripcord to be manually pulled, pocket means upon said pack having anopening disposed in a position remote from said cones, said pocket meansbeing substantially closed in a position adjacent said cones forsecuring said drive means against movement towards said cones, saidpocket means being mounted upon a portion of said pack closely adjacentto said pins with a line of action extending through said openingaligned with the line of action of said pins, said drive means beinginserted within said pocket which disposes its line of action in linewith that of said pins and with said opening in said pocket, adetachable coupling being connected in said actuating circuit, one endof said detachable coupling being connected to saidautomatically-actuable drive means, and the other end of said detachablecoupling attached to said pack for disarming said circuit when saidripcord is manually pulled.

13. An automatic device for opening a parachute at a predeterminedaltitude comprising drive means for providing an electrically-actuatedthrust, an altimeter means incorporating a visible movablealtitude-indicating element and an associated direct-reading visiblereference element arranged to directly denote altitude in cooperationwith each other, manually-adjustable means connected to said referenceelement for adjusting it with reference to the ground level position ofsaid movable element to indicate a zero altitude at ground level,signalling means mounted upon said reference element for providing asignal when said moving element assumes a predetermined relationshipwith said reference element at said predetermined altitude, and anactuating circuit connecting said signalling means with said drive meansfor causing it to provide a parachute pack opening thrust at saidpredetermined altitude.

14. An automatic device for electrically actuating a power-operatedparachute-opening drive means to open a parachute at a predeterminedaltitude comprising an altimeter incorporating a movable indicatingelement and an adjustable face which cooperate to directly denotealtitude to a viewer, manually-adjustable means connected to saidadjustable face for adjusting it with reference to said indicatingelement at ground level to indicate a zero altitude at ground level, anactuating means connecting said movable indicating element with saiddrive means for actuating said drive means to provide a parachuteopeningthrust at said predetermined altitude, said actuating means including aswitch means having one of its contacts mounted upon said movableindicating element and the other of its contacts mounted upon said facein a disposition relative to said face to be engaged by said one contactupon said needle at a predetermined position corresponding to saidpredetermined altitude, said actuating means including an actuatingcircuit connecting said switch means with said drive means, and anarming means operativcly connected with said actuating means forinactivating it until said indicating element moves upwardly past saidpredetermined position and for activating said actuating means upon thedownward movement of said movable indicating element to saidpredetermined position whereby said actuating circuit is completed whensaid one of said contacts upon said movable indicating element isengaged with said other of said contacts.

15. A device as set forth in claim 14 wherein said movable indicatingelement comprises a needle, a movable sector is concentrically mountedabout said needle, said other contact means which is mounted in apredetermined position relative to said face is mounted upon saidsector, and said arming means comprises a stationary energized contactmeans which is engageable by a portion of said sector.

16. A device as set forth in claim 15 wherein said actuating circuit isgrounded to a conductive portion of the mechanism of said altimeter forelectrically connecting it to said needle.

17. A device as set forth in claim 15 wherein said sector is made ofconductive material, said sector includes a foot which engages saidenergizing contact to arm said actuating circuit, and a pin extends fromsaid sector toward said face for engaging said needle.

18. A device as set forth in claim 17 wherein a radially directed slotis provided in said sector for providing a visual indication of theportion of said face with which it is aligned when said foot is engagedwith said energizing contact, and indicia are provided upon said face inline with said slot for indicating the armed condition.

19. A device as set forth in claim 17 wherein a clamp is provided forholding said sector out of engagement with said energizing contact.

20. A device as set forth in claim 19 wherein said clamp and saidenergizing contact comprise dual spring fingers, and said foot includesspaced toes which interlock with one of said fingers upon said clamp andenergizing contact means.

References Cited in the file of this patent UNITED STATES PATENTS McCabeJan. 9, White Mar. 29, McCabe May 3, Ogden et al. Apr. 18, Quilter May2, Johnson June 5, Hatfield Apr. 27, Gaylord May 1, Moy et al. July 28,

FOREIGN PATENTS France Dec. 29, France Apr. 1, France July 28,

1. A DEVICE FOR OPENING A PARACHUTE PACK SECURED BY PINS ATTACHED TO ARIPCORD AND INSERTED INTO CONES COMPRISING AN ELECTRICALLY-ACTUATEDDRIVE MEANS INCLUDING A MOVABLE ELEMENT MOUNTED WITHIN A STATIONARYPORTION, AN ALTITUDE-SENSING MEANS FOR PROVIDING A SIGNAL AT APREDETERMINED ALTITUDE, AN ACTUATING CIRCUIT CONNECTING SAID SENSINGMEANS TO SAID DRIVE MEANS FOR CAUSING IT TO PROPEL SAID MOVABLE ELEMENTIN RESPONSE TO SAID SIGNAL, COUPLING MEANS CONNECTING SAID MOVABLEELEMENT WITH SAID RIPCORD TO PERMIT SAID RIPCORD TO BE PULLED, POCKETMEANS UPON SAID PACK HAVING AN OPENING DISPOSED IN A POSITION REMOTEFROM SAID CONES, SAID POCKET MEANS BEING SUBSTANTIALLY CLOSED IN APOSITION ADJACENT SAID CONES FOR SECURING SAID DRIVE MEANS AGAINSTMOVEMENT TOWARDS SAID CONES, SAID POCKET MEANS BEING MOUNTED UPON APORTION OF SAID PACK CLOSELY ADJACENT TO SAID PINS WITH A LINE OF ACTIONEXTENDING THROUGH SAID OPENING ALIGNED WITH THE LINE OF ACTION OF SAIDPINS, SAID DRIVE MEANS BEING INSERTED WITHIN SAID POCKET WHICH DISPOSESITS LINE OF ACTION IN LINE WITH THAT OF SAID PINS WITH SAID OPENING INSAID POCKET, AND A HANDLE BEING DIRECTLY CONNECTED TO SAID STATIONARYPORTION OF SAID DRIVE MEANS TO PERMIT SAID RIPCORD TO BE MANUALLY PULLEDTHROUGH SAID COUPLING WHICH CONNECTS SAID MOVABLE ELEMENT OF SAID DRIVEMEANS TO SAID RIPCORD.